Nonlinear maternal effects on personality in a rodent species with fluctuating densities

Consistent among individual variation in behavior,or animal personality,is present in a wide variety of species.This behavioral variation is maintained by both genetic and environmental factors.Parental effects are a special case of environmental variation and are expected to evolve in populations experiencing large fluctuations in their environment.They represent a non-genetic pathway by which parents can transmit information to their offspring,by modulating their personality.While it is expected that parental effects contribute to the observed personality variation,this has rarely been studied in wild populations.We used the multimammate mouse Mastomys natalensis as a model system to investigate the potential effects of maternal personality on offspring behavior.We did this by repeatedly recording the behavior of individually housed juveniles which were born and raised in the lab from wild caught females.A linear correlation,between mother and offspring in behavior,would be expected when the personality is only affected by additive genetic variation,while a more complex relationship would suggests the presence of maternal effects.We found that the personality of the mother predicted the behavior of their offspring in a non-linear pattern.Exploration behavior of mother and offspring was positively correlated,but only for slow and average exploring mothers,while this correlation became negative for fast exploring mothers.This may suggests that early maternal effects could affect personality in juvenile M.natalensis,potentially due to density-dependent and negative frequency-dependent mechanisms,and therefore contribute to the maintenance of personality variation.

Maternal Thermal Effects on Female Reproduction and Hatchling Phenotype in the Chinese Skink(Plestiodon chinensis)

We maintained gravid Chinese skinks(Plestiodon chinensis) at three constant temperatures(25, 28 and 31 °C) during gestation, and randomly assigned eggs from each female to one of the same three temperatures for incubation to determine maternal thermal effects on female reproduction and hatchling phenotype. Maternal temperature affected egg-laying date, hatching success and hatchling linear size(snout-vent length, SVL) but not clutch size, egg size, egg component, and embryonic stage at laying. More specifically, females at higher temperatures laid eggs earlier than did those at low temperatures, eggs laid at 31 °C were less likely to hatch than those laid at 25 °C or 28 °C, and hatchlings from eggs laid at 31 °C were smaller in SVL. Our finding that maternal temperature(pre-ovipositional thermal condition) rather than incubation temperature(post-ovipositional thermal condition) affected hatching success indicated that embryos at early stages were more vulnerable to temperature than those at late stages. Our data provide an inference that moderate maternal temperatures enhance reproductive fitness in P. chinensis.

Clonal Transgenerational Effects Transmit for Multiple Generations in a Floating Plant

Environmental conditions of a parent plant can influence the performance of their clonal offspring,and such clonal transgenerational effects may help offspring adapt to different environments.However,it is still unclear how many vegetative generations clonal transgenerational effects can transmit for and whether it depends on the environmental conditions of the offspring.We grew the ancestor ramets of the floating clonal plant Spirodela polyrhiza under a high and a low nutrient level and obtained the so-called 1^(st)-generation offspring ramets of two types(from these two environments).Then we grew the 1^(st)-generation offspring ramets of each type under the high and the low nutrient level and obtained the so-called 2^(nd)-generation offspring ramets of four types.We repeated this procedure for another five times and analyzed clonal transgenerational effects on growth,morphology and biomass allocation of the 1^(st)-to the 6^(th)-generation offspring ramets.We found positive,negative or neutral(no)transgenerational effects of the ancestor nutrient condition on the offspring of S.polyrhiza,depending on the number of vegetative generations,the nutrient condition of the offspring environment and the traits considered.We observed significant clonal transgenerational effects on the 6^(th)-generation offspring;such effects occurred for all three types of traits(growth,morphology and allocation),but varied depending on the nutrient condition of the offspring environment and the traits considered.Our results suggest that clonal transgenerational effects can transmit for multiple vegetative generations and such impacts can vary depending on the environmental conditions of offspring.

Effects of Maternal Marginal Iodine Deficiency on Interactions between Cerebellar Bergmann Glia Cells and Purkinje Cells in Rat Offspring

Iodine deficiency （ID） during early pregnancy has an adverse effect on children＇s psychomotor and motor function but the mechanism has not been clarified. Therefore, our aim was to study the effect of maternal marginal ID on cerebellar neurodevelopment and the underlying mechanism. After obtaining marginal ID rats, we examined interactions between Bergmann gila cells （BGs） and Purkinje cells （PCs） using immunofluorescence and expression of the glutamate transporter and receptor by western blot. Our results showed that marginal ID reduced the number of contacted points between BGs and PCs,

Research Progress of Maternal Environmental Effects in Resource-based Regions

Heavy metal pollution is common in resource-based regions.However,the morphological,physiological and biochemical mechanisms of plants transmitting environmental information to their offspring in environments polluted by heavy metals have not been studied yet.Taking soybean,an annual self-pollinated plant in Huang-Huai-Hai region,as the research object,the morphological,physiological and biochemical indexes and heavy metal enrichment and distribution characteristics of plants under heavy metal stress were monitored continuously for about three generations,and the trans-generational differences of soybean reproduction,vegetative growth,stress resistance and life cycle in heavy metal stress environment were elucidated.The results will be helpful to better understand the long-term adaptive strategy of plants to heavy metal stress and provide the theory basis for ecological security of soybean and other crops under heavy metal stress.

Effects of Maternal Linseed Oil Supplementation on Metabolic Parameters in Cafeteria Diet-induced Obese Rats

Because linseed oil may influence maternal and fetal metabolisms, we investigated its role in the modulation of lipid metabolism in cafeteria diet-induced obese rats and their offspring. Female Wistar rats were fed control or cafeteria food, which were either supplemented or not supplemented with linseed oil （5%） for I month before and during gestation. At parturition, serum and tissue lipids and enzyme activities were analyzed. Cafeteria diet induced adverse metabolic alterations in both mothers and offspring. Linseed oil improved metabolic status. In conclusion, linseed oil displayed health benefits by modulating tissue enzyme activities in both obese mothers and their newborns.

Analysis of seed and maternal genetic effects on cooking quality characters in indica hybrid rice

We analysed seed and maternal genetic effects on characters of cooking quality in indica hybrid rice by using the model for quantitative characters of seeds of cereal crops. Incomplete diallel crosses were made by using six male sterile lines (Zhenshan 97A, Erjiuqing A, Erjiunan 1A, V20A, Zhe’nan 1A and Zhe’nan 3A)as females and three restorer lines(Cezao 2-2, T49 and 26715)as males. Sampled seeds were used to measure the cooking quality characters, including amylose content(%), gelatinization temperature(alkali spreading score)and gel consistency(mm). Results indicated that some rice cooking quality characters were controlled by both seed genes and maternal genes (see table). Gel consistency was mainly controlled by maternal effects, but also

Epistasis and Maternal Effect in Resistance to Puccinia coronata Cda.f.sp. avenae Eriks in Oats(Avena sp.)

The objective of this paper was to investigate the mode of heredity for resistance in oats （Avena sp.） to crown rust caused by Puccinia coronata Cda. f. sp. avenae Eriks, Eight generations of 2 crosses were used to estimate genetic effects and narrow-sense heritability （NSH）. Separate generation means analysis （GMA） indicated a complex gene action controlling this trait with additive, dominance, epistatic and maternal effects （ME）. The genetic model which assumed no epistasis and no ME did not accurately describe the resistance to P. coronata. In both crosses, the digenic epistatic model with ME was sufficient to explain variation in generation means for isolate CRec58 and isolate CRec46. Additive dominance and epistatic components were negative in most cases, suggesting that gene effects contributed more to the resistance than to the susceptibility. The estimated values of NSH were 15-99% depending upon the cross and isolates. The results indicated that appropriate choice of maternal parent and recurrent selection would increase resistance to crown rust in oats.

Effect of TCDD on Maternal Toxicity and Chorionic Gonadotropin──Bioactivity in the Immediate Post-implantation Period of Macaque

The purpose of this experiment was to observe the alterations in bioactivity of chorionic gonadotropin (CG) associated with early fetal loss (EFL), induced by the environmental toxin TCDD (2,3,7,8\|tetrachlorodibenzo\| p \|dioxin) in the cynomolgus macaque. Ten of twelve females administered single doses of 1, 2 or 4 μg/kg TCDD on gestational day (GD) 12 had EFL from ten to twenty days later. Seven control animals treated only with the vehicle had normal pregnancies. Blood samples were repeatedly collected for hormone evaluation, from two days before treatment to thirty\|one days following treatment. Immunoreactive monkey chorionic gonadotropin (mCG) was measured in serum using ELISA, and bioactive mCG was measured using a luminescence LH/CG bioassay. No change in immunoreactive mCG levels was detected as a result of TCDD, treatment, but bioactive mCG levels were significantly lower in TCDD\|treated animals compared to controls. This change in bioactivity of mCG was also reflected in the ratio of mCG bioactivity to mCG immunoreactivity (B/I ratio) which began to rise in normal pregnancies by GD 20, but did not rise in TCDD treated animals. These results demonstrate that normal pregnancy in the monkey, as in humans, is characterized by a post\|implantation change in the B/I ratio of CG. These findings therefore suggest that changes in the production of bioactive CG may be used as a biomarker of environmental toxicant exposures which lead to EFL.

Interval Mapping of Quantitative Trait Loci Underlying Triploid Endosperm Traits Using F_3 Seeds

A statistical method for mapping quantitative trait loci （QTLs） underlying endosperm traits is proposed. The method is based on a genetic model containing both the direct effects and maternal effects of an endosperm QTL and on an experimental design termed two-stage hierarchical design, in which the trait information is obtained from F3 endosperms and molecular marker information is obtained from F2 plants and F3 embryos （plants）. Results of computer simulations indicate that the method can efficiently map endosperm QTLs and precisely estimate both the direct and maternal effects of endosperm QTLs when the sample size is sufficiently large.

Assigning hatchlings to eggs:Is relative mass assignment an accurate method?

Background: Accurately assigning hatchlings to the eggs from which they hatched is a prerequisite to understanding how the composition and environment of eggs affect the growth and survival of nestlings. Correctly assigning hatchlings to their eggs can be a challenging endeavor, however, because multiple eggs within the same clutch can hatch at essentially the same time. Egg and hatchling mass are highly correlated in most bird species, and thus assigning eggs to hatchlings using their relative mass(e.g., matching the heaviest hatchling to the heaviest candidate egg) could prove extremely useful.Methods: To assess its potential utility, I applied relative mass assignment(RMA) retrospectively to a dataset of 133 Common Grackle(Quiscalus quiscula) nests in which all egg-hatchling dyads were determined unequivocally.Results: I found that RMA correctly assigned approximately 90% of hatchlings to their eggs when 2-4 hatchlings were present between checks. The number of nests in which hatchlings could not be assigned to their egg, however, increased monotonically from 13 to 46 to 78% for nests containing 2, 3, and 4 hatchlings, respectively, due to the greater likelihood that the mass of hatchlings or their candidate eggs was identical.Conclusions: Although RMA correctly identified the vast majority of egg-hatchling dyads, researchers should use this method with caution, because it will always inflate positive egg-size effects and thus could potentially result in erroneously reporting significant effects.

Estimates of genetic and phenotypic parameters for weight and length in Paralichthys olivaceus(Temminck et Schlegel)

The complete diallel cross design was employed to estimate the genetic parameters of the growth of Japanese flounder （Paralichthys olivaceus）. A total of 60 full-sib families were cultivated and two growth-related traits, body weight （BW） and body length （BL）, were examined at average 2, 3 and 8 months of age respectively, with 1 800 individuals measured in each age group （30 per family）. Based on the additive-dominance-maternal-effect genetic analysis model, the restricted maximum likelihood approach was used to estimate various （co）variance components. The results showed that narrow-sense heritability estimates of BW and BL were respectively： 0.29 ± 0.01 and 0.22 ± 0.02 at 2 months of age, 0.32 ± 0.02 and 0.30 ± 0.04 at 3 months of age, 0.48 ± 0.04 and 0.40 ± 0.05 at 8 months of age; broad-sense heritability estimates were respectively： 0.44 ± 0.02 and 0.54 ± 0.04 at 2 months of age, 0.35 ± 0.01 and 0.36 ± 0.03 at 3 months of age, 0.49 ± 0.03 and 0.45 ± 0.04. All heritabilities were statistically significant （P 0.05）. Additive genetic correlations between BW and BL at 2, 3 and 8 months of age were consistently positive and highly significant （P 0.01）： 0.93 ± 0.02, 0.95 ± 0.03 and 0.92 ± 0.03 respectively. Maternal effect was significant （P 0.05） only at 2 months of age, and was not detected at 3 and 8 months of age. According to the heritability estimates, the mass selection strategy should be efficient for the breeding of Japanese flounder.

Growth of eight Pacific abalone families at three temperatures

Growth rates, measured as shell length and body weight daily growth, were studied in the eight families of Pacific abalone, Haliotis discus hannai Ino, reared at 12, 16 and 20 ℃for 40 d respectively. The results show that J1Rh family grew the best at 12 ℃, with growth rates of (32.88±4.66) μm/d and (5.24±1.84) mg/d. C1Jm family had the highest growth rates of (58.00±2.00) μm/d and (9.71±1.21) mg/d at 16 ℃. J1Jm family ranked the first at 20 ℃, with growth rates of (66.00±1.76) μm/d and (10.99±0.34) mg/d. RjRh family had the slowest growth rates at all three temperatures. Shell length growth rates were 18.25, 33.00 and 43.13 μm/d respec- tively, while body weight growth rates were 2.47, 2.56 and 4.75 mg/d respectively. Both temperature and family had significant effect on growth rates (P< 0.05). At 16 and 20 ℃, maternal effects on growth rates were not significant (P> 0.05), but paternal effects on growth rates were significant (P< 0.05). Results of this study indicate genetic difference among the families and importance of select- ing male breeders in the commercial hatchery.

Effects of maternal stress induced by predator odors during gestation on behavioral and physiological responses of offspring in Brandt’s vole(Lasiopodomys brandtii)

Maternal effects play a crucial role in regulating populations of small mammals and anti-predator behaviors of offspring.The present study investigated the effects of maternal stress induced by exposure to predator odors during gestation on the behavioral and physiological responses of offspring in Brandt’s vole(Lasiopodomys brandtii).Effects included changes in growth,behaviors,hormone levels in serum,and fosB/ΔfosB mRNA and FosB/ΔFosB protein expression in the hypothalamus.Our results showed that when pregnant voles were exposed to cat and rabbit urine odors for 18 days(1 h/day),the weight of the female offspring decreased;however,the thymus and ovary indices increased,compared with the control group.Male offspring of voles exposed to cat odor spent more time exploring and foraging,and showed a decrease in corticosterone(CORT)compared with voles in the control group.Both fosB/ΔfosB mRNA and FosB/ΔFosB protein expressions were downregulated in the hypothalamus of male offspring in the cat odor-exposed group compared to that in offspring in the control group.However,the mRNA levels of fosB/ΔfosB in the hypothalamus of female offspring did not decrease in response to cat urine odor.Our findings suggested that maternal stress induced by predator odors during gestation restrained the growth of female offspring and increased the duration of exploring and foraging behaviors of male offspring by regulating the HPA axis,which,in turn,reduced the sensitivity of offspring to unfamiliar environments and increased their probability of becoming prey.

Sex-specific effects of inbreeding and early ife conditions on the adult oxidative balance

Inbreeding negatively affects various life-history traits, with inbred individuals typically having lower fit- ness than outbred individuals （=inbreeding depression）. Inbreeding depression is often emphasized under environmental stress, but the underlying mechanisms and potential long-lasting consequences of such inbreeding-environment interactions remain poorly understood. Here, we hypothesize that inbreeding-environment interactions that occur early in life have long-term physiological effects, in partic- ular on the adult oxidative balance. We applied a unique experimental design to manipulate early life conditions of inbred and outbred songbirds （Serinus canaria） that allowed us to separate prenatal and postnatal components of early life conditions and their respective importance in inbreeding-environment interactions. We measured a wide variety of markers of oxidative status in adulthood, resulting in a com- prehensive account for oxidative balance. Using a Bayesian approach with Markov chain Monte Carlo, we found clear sex-specific effects and we also found only in females small yet significant long-term effects of inbreeding-environment interactions on adult oxidative balance. Postnatal components of early life conditions were most persuasively reflected on adult oxidative balance, with inbred females that experienced disadvantageous postnatal conditions upregulating enzymatic antioxidants in adulthood. Our study provides some evidence that adult oxidative balance can reflect inbreeding-environment inter- actions early in life, but given the rather small effects that were limited to females, we conclude that oxida- tive stress miaht have a limited role as mechanism underlvina inhre.e.dina-envirnnme.nt inte.raetinn.q_

Parental ecological history can differentially modulate parental age effects on offspring physiological traits in Drosophila

Parents adjust their reproductive investment over their lifespan based on their condition,age,and social environment,creating the potential for inter-generational effects to differentially affect offspring physiology.To date,however,little is known about how social environments experienced by parents throughout development and adulthood influence the effect of parental age on the expression of life-history traits in the offspring.Here,I collected data on Drosophila melanogaster offspring traits(i.e.,body weight,water content,and lipid reserves)from populations where either mothers,fathers both,or neither parents experienced different social environments during development(larval crowding)and adulthood.Parental treatment modulated parental age effects on offspring lipid reserves but did not influence parental age effects on offspring water content.Importantly,parents in social environments where all individuals were raised in uncrowded larval densities produced daughters and sons lighter than parental treatments which produced the heaviest offspring.The peak in offspring body weight was delayed relative to the peak in parental reproductive success,but more strongly so for daughters from parental treatments where some or all males in the parental social environments were raised in crowded larval densities(irrespective of their social context),suggesting a potential father-to-daughter effect.Overall,the findings of this study reveal that parental ecological history(here,developmental and adult social environments)can modulate the effects of parental age at reproduction on the expression of offspring traits.

Climate change,thermal niches,extinction risk and maternal-effect rescue of toad-headed lizards,Phrynocephalus,in thermal extremes of the Arabian Peninsula to the Qinghai-Tibetan Plateau

Determining the susceptibility of species to changing thermal niches is a major goal for biologists.In this paper we develop an eco-physiological model of extinction risk under climate change premised on behavioral thermoregulation.Our method downscales operative environmental temperatures,which restrict hours of activity of lizards,hr,for present-day climate(1975)and future climate scenarios(2070).We apply our model using occurrence records of 20 Phrynocephalus lizards(or taxa in species complexes)drawn from literature and museum records.Our analysis is phylogenetically informed,because some clades may be more sensitive to rising temperatures.The limits for computed hr predict local extirpations among Phrynocephalus lizards at continental scales and delineate upper boundaries of thermal niches as defined by Extreme Value Distributions.Under the 8.5 Representative Concentration Pathway scenario,we predict extirpation of 64%of local populations by 2070 across 20 Phrynocephalus species,and 12 are at high risk of total extinction due to thermal limits being exceeded.In tandem with global strategies of lower CO_(2) emissions,we propose regional strategies for establishing new national parks to protect extinction-prone taxa by preserving high-elevation climate refugia within existing sites of species occurrence.We propose that evolved acclimatization–maternal plasticity–may ameliorate risk,but is poorly studied.Previous studies revealed that adaptive maternal plasticity by thermoregulating gravid females alter progeny thermal preferences by±1℃.We describe plasticity studies for extinction-prone species that could assess whether they might be buffered from climate warming–a self-rescue.We discuss an epigenetic framework for studying such maternal-effect evolution.

Zbed3 participates in the subcortical maternal complex and regulates the distribution of organelles

We previously identified a subcortical maternal complex （SCMC） that is essential for early embryogenesis and female fertility in mice. However, the molecular mechanism by which the SCMC affects female fertility remains largely uncharacterized. Here, we report that a novel maternal protein, zinc finger BED-type containing 3 （Zbed3）, participates in the SCMC. Depletion of maternal Zbed3 results in reduced fecundity of females, because of the impaired and delayed development in a proportion of mutant embryos. The loss of maternal Zbed3 results in asymmetric zygotic division and abnormal distributions of organeUes in the affected oocytes and zygotes, similar to the phenotypes observed in females with disrupted core SCMC genes. Further investiga- tion revealed that these phenotypes are associated with disrupted dynamics of microtubules and/or formation of cytoplasmic lat- tices （CPLs）. The stability and localization of Zbed3 depend on, but are not required for, the formation of the SCMC. Thus, our data suggest Zbed3 as one of downstream proteins mediating SCMC functions and provide further insights into the roles of the SCMC and CPLs in female fertility.

Phenotypic consequences of maternally selected nests:a cross-fostering experiment in a desert lizard

Despite the importance of maternally selected nests in shaping offspring phenotypes,our understanding of how the nest environment affects embryonic development and offspring traits of most non-avian reptiles is rather limited largely due to the logistical difficulty in locating their nests.To identify the relative contributions of environmental(temporal[seasonal]and spatial[nest-site])and intrinsic(clutch)factors on embryonic development and offspring traits,we conducted a cross-fostering experiment by swapping eggs between maternally-selected nests of the toad-headed agama(Phrynocephalus przewalskii)in the field.We found that nest environment explained a large proportion of variation in incubation duration,hatching success,and offspring size and growth.In contrast,clutch only explained a small proportion of variation in these embryonic and offspring traits.More significantly,compared with spatial effects,seasonal effects explained more phenotypic variation in both embryonic development and offspring traits.Eggs laid early in the nesting season had longer incubation durations and produced smaller hatchlings with higher post-hatching growth rates than did later-laid eggs.Consequently,hatchlings from early-laid eggs reached larger body sizes prior to winter.In addition,we found that female toad-headed agama did not select nests specific to reaction norms of their own offspring because hatchlings from original or translocated nests had similar phenotypic traits.Overall,our study demonstrates the importance of seasonal variation in nest environments in determining embryonic development and offspring phenotypes,which has not been widely appreciated at least in non-avian reptiles.

The importance of trans-generational effects in Lepidoptera

The importance of trans-generational effects in shaping an individuals＇ phenotype and fitness, and consequently even impacting population dynamics is increasingly apparent. Most of the research on trans-generational effects still focuses on plants, mammals, and birds. In the past few years, however, increasing number of studies, especially on maternal effects, have highlighted their im- portance also in many insect systems. Lepidoptera, specifically butterflies, have been used as model systems for studying the role of phenotypic plasticity within generations. As ectotherms, they are highly sensitive to environmental variation, and indeed many butterflies show adaptive phenotypic plasticity in response to environmental conditions. Here, we synthesize what is known about trans-generational effects in Lepidoptera, compile evidence for different environmental cues that are important drivers of trans-generational effects, and point out which offspring traits are mainly impacted. Finally, we emphasize directions for future research that are needed for better understanding of the adaptive nature of trans-generational effects in Lepidoptera in particular, but potentially also in other organisms.